The present invention relates to a display apparatus which magnifies an image and projects the image on a screen by use of light valves such as image display elements. The present invention relates to a display apparatus having a dust prevention mechanism for preventing dust from entering an inside of the display apparatus when a dust filter is detached.
In U.S. Pat. No. 5,946,078, a structure of a fan disposed to an inlet of air flow of a duct, and a structure of filters attached before and behind the fan, are disclosed. Only the filter detachably attached upstream of the air flow is exchanged while a shutter is closed, and the fan is stopped.